Percussion hammer

ABSTRACT

There is provided a percussion hammer of the type including a cylinder and a piston operable in the cylinder connected to a ram through a piston rod. Valve means are provided for cycling working fluid into and exhausting the working fluid from the cylinder to cycle the tool through power and return strokes. The cycling valve is controlled by a suitable actuator or slide bar connected to the ram and provided with cams for actuating a trip. The ram is provided with removable weights so as to permit alteration of the operating characteristics of the hammer. In addition there is provided an improved means of fastening the piston rod to the ram and of connecting the slide bar to the ram. A detent is provided for latching the valve trip in the desired position.

United States Patent [72] Inventor George C. Wandell Soddy, Tenn. [21]Appl. No. 846,720 [22] Filed Aug. 1, 1969 [45] Patented Mar. 2, 1971[73] Assignee Vulcan Iron Works Inc.

Chattanooga, Tenn.

[54] PERCUSSION HAMMER 7 Claims, 8 Drawing Figs.

[52] US. Cl. 173/90, 91/277,173/126 [51] Int. Cl B25d 9/00 [50] Field ofSearch 173/49, 90, 126,128,131;91/277 [56] References Cited UNITEDSTATES PATENTS 696,480 4/1902 Pierce 173/126 2.897,782 8/1959 Kennedy173/126 2,990,022 6/1961 Mueller et al 173/49 3,245,482 4/1966 Williamset al. 173/126 3,357,315 12/1967 Adams et al. 91/277 PrimaryExaminer-James A. Leppinik Attorney-Mason, Kolehmainen, Ratiiburn andWyss suitable actuator or slide bar connected to the ram and pro-' videdwith cams for actuating a trip. The ram is provided with removableweights so as to permit alteration of the operating characteristics ofthe hammer. In addition there is provided an improved means of fasteningthe piston rod to the ram and of connecting the slide bar to the ram. Adetent is provided for latching the valve trip in the desired position.

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ATT'YS PERCUSSION HAMMER The present invention relates to a percussionhammer, and more particularly to a percussion, hammer of the typegenerally used for driving piles and the like. Such a hammer may bedriven by steam, compressed air, or other working fluid.

Commercially available percussion hammers of the type used for drivingpiles and the like may be either of single-acting type wherein the ramand associated driving structure is raised by the working fluid isexhausted and the ram and associated driving parts are dropped bygravity, or a double-acting type wherein the ram and associated pistonis driven through its power stroke by working fluid acting with thegravity. The present invention is described with reference toapplications on a single-acting type hammer, but the principlesdescribed are equally applicable topercussion hammers of thedouble-acting type. Commercially such percussion hammers aremanufactured in several different sizes. The size of a pile drivinghammer is selected by the'amount of energy that the hammer is capable ofdelivering, and is dependent in part on the weight of the ram. Becauseof the many require ments for different size hammers, it would bedesirable to have available the means to convert one size of hammer toanother, either in manufacture or in the field, with the least amount ofeffort andexpense. Moreover heretofore certain difficulties have arisenwith the manufacture, maintenance, and repair of percussion hammers. Onearea of difficulty has been the connections between the piston rod andthe slide bar with the ram of the percussion hammer. Heretofore therehas been em-- ployed ram keys and the slide bar keys with suitable locksthat have been troublesome. In addition, difficulty has been experiencedwith the trip of the control valve bouncing after reaching its maximumpositions.

Accordingly, it is an object of the present invention to provide a newand improved percussion hammer.

A further object of the present invention is to provide a percussionhammer which may readily be converted from one size to another, eitherduring manufacture or in the field.

Yet a further object of the present invention is to provide a new andimproved means for fastening a piston rod to the ram of a percussionhammer.

Still another object of the present invention is to provide a new andimproved means for securing the slide bar of a percussion hammer to theram thereof.

Still another object of the present invention is to provide means forminimizing instability of the control valve because of bounce and thelike.

Further objects and advantages of the present invention will becomeapparent as the following description proceeds and the features ofnovelty which characterize the invention will be pointed out withparticularity in the claims annexed to and forming a part of thespecification.

In accordance with these and other objects there is provided an improvedpercussion hammer adapted for pile driving and the like. A commercialpercussion hammer includes a cylinder with a piston operable in thecylinder. Suitable working fluid is cycled into and out of the cylinderto provide cycling of the piston. The piston is connected to a ram whichin turn provides percussion blows on a base or head resting on a pile.Suitable valve and control means are provided for controlling thecycling of the working fluid. On such known valving arrangement is morefully described and claimed in U.S. Pat. No. 3,357,315 granted Dec. 12,1957 to Adams et al. and assigned to the same assignee as the presentinvention. In accordance with the present invention the ram is providedwith cavity means adapted to receive removable weights thereby providingfor altering the amounts of energy that the hammer delivers per blow.Thus the hammer may be readily converted to different sizes both duringmanufacture and in the field. In addition, the ram is provided with acentrally located piston rod bore for receiving one end of the pistonrod, and the lower end of the piston rod is provided with an outwardlyand downwardly extending taper. The piston rod is retained within therod bore of the ram by a split bushing secured with the bore. Moreoverthe ram is provided with a counterbore for securing the slide bar, andan improved slide bar is operatively positioned to control the valvemeans connected to the ram by a flexible connector such as a cableconnector, the lower end of which is bolted or otherwise secured throughthe ram. A trip detent for the valve mechanism is provided to moresecurely locate the valve controlling the working fluid.

Advantageously, the removable weights on the ram permit conversion ofthe pile driving hammer to a desired size, both during manufacture andin the field. Thus it is possible during manufacture to standardize asmaller number of hammers and parts; and. permits the purchase andoperation of a single hammer to be used where different pile drivingenergy requirements are present. The fastening of the piston rod to theram and the rope wire fastening device securing the slide bar to the ramboth permit elimination of the present ram and slide bar keys. Theimproved trip detent in the hammer improves the stability of the valveand prevents the valve from bouncing back after reaching its maximumpositions.

For better understanding of the present invention, reference may be hadto the accompanying drawings wherein:

FIG. 1 is a side elevational view of the improved percussion hammer,partly in broken away section;

FIG. 2 is a cross-sectional view of the percussion hammer of FIG. 2,taken along line 22 of FIG. 1;

FIG. 3 is an enlarged view of the ram according to the present inventiontaken along line 3-3 of FIG. 2;

FIG. 4 is a cross-sectional view of the ram of the improvedpercussionhammer, taken along line 4-4 of FIG. 3;

FIG. 5 is an enlarged fragmentary view of the slide bar to ramconnection according to the present invention;

FIG. 6 is an enlarged view of the piston rod to ram connection; and

FIGS. 7 and 8 illustrate the trip detent on the valve trip according tothe present invention.

Referring now to the drawings, and particularly to FIGS. 1 and 2thereof, there is illustrated an improved percussion hammer 10 of thetype adapted to drive piles and the like The percussion hammer 10 isoperated by suitable working fluid, such as steam, in a known manner.The percussion hammer 10 includes a housing 12 defining a cylinder 13.The cylinder 13 is closed at its upper end by a cylinder head 14 havinga head sheave l5, and is closed at its lower end by an endwall defininga stuffing box 16. The sheave. 15 permits hoisting of the percussionhammer 10 by a crane or other suitable means for placement on top of apile.

The housing 12 additionally includes: a base 18 connected to thecylinder 13 by opposed side guide channels 19 and columns. A ramassembly 20 having a ram housing 20a is adapted to be reciprocatedvertically guided by the columns. A piston 21 in the cylinder 13 isconnected to the ram assembly 20 by a suitable piston rod 22 whichextends through suitable packing 23 in the stuffing box 16.

The illustrated tool is of the single-acting type, wherein the workfluid enters the lower end of the cylinder 13 so as to raise the piston21 along with its associated. piston rod 22 and ram assembly 20 from theposition illustrated in solid in FIG. 2 to the position illustrated inphantom therein. As the piston 21 approaches its top position theworking fluid below the piston 21 is exhausted to the atmosphere,permitting the ram assembly 20 and its associated piston rod 22 andpiston 21 to drop by gravity. A ram point 24 carried by the ram assembly20 will strike a driving head (not shown) to provide percussion ordriving loads to pile. The control of the working fluid into and out ofthe cylinder 13 is through a valve assembly 28, of known design, andmore fully described in the above mentioned Adams et al. patent.However, briefly, the valve assembly 28 includes a steam chest 29 havinga supply tap 30 for connection to a source of working fluid as steam. Inaddition the valve assembly 28 includes an exhaust passageway 31 openingto the atmosphere. A rotary valve element 32 rocks between the positionillustrated in FIG. 2, connecting the steam chest 29 to the lower end ofthe cylinder 13 through a suitable passageway 33, counterclockwise to asecond position wherein the passageway 33 is connected to the exhaustpassageway 31 so as to exhaust the lower end of the cylinder 13. A trip35 is connected to a shaft 36 carrying the valve element 32 andextending through the steam chest 29 so as to be in the path of a slidebar 40 secured to the ram assembly for reciprocation therewith. The trip35, as best illustrated in FIGS. 7 and 8, includes a pair of cam or camarms 41 and 42, and the slide bar 40 has a pair of spaced cam members orcam actuating members 44 and 45 arranged to intercept respectively thecam arms 41 and 42 so as to rock the trip 35. Thus it will be understoodthat as the piston 21 with its pistonrod 22 and associated ram assembly20 reaches the bottom of the stroke, the cam 44 will intercept the arm41 and rotate the valve element 32 to the position illustrated in FIG.2, thus admitting pressurized fluid into the lower end of the cylinder13 to raise the piston 21. As the piston'21 approaches the upper end ofits stroke, the cam actuating member 45 will intercept the cam arm 42and rock the valve element 32 clockwise, as viewed in FIG. 2, so as toexhaust the working fluid below the piston 21 and permit dropping of theram assembly 20 and associated piston 21 and piston rod 22. An exhaustopening 46 near the upper end of the cylinder 13 permits exhaust of thefluid above the piston 21 during the up stroke of the piston 21, andmoreover provides for a pneumatic cushion after the piston 21 passes thepassageway 46.

The ram assembly 20 is provided with opposed grooves 48 defining tracksreceiving the guide channels 19. Thus the ram assembly 20 is mounted forreciprocal motion between the guide channels 19. In accordance with afeature of the present invention, the ram assembly 20 is provided withmeans for receiving removable weights so as to permit conversion of thepercussion hammer to different sizes of applied energy. Specifically, inthe illustrated embodiment, the housing 20a of the ram assembly 20 isprovided with a pair of upwardly opening cavities 201;, each containinga removable cylindrical weight 50. The top of each cavity 20b is 'closedby a coverplate 51 secured to the housing 20a in any suitable manner aswith the bolts 52.

The ram housing 20a is provided with a centrally located piston rod borefor receiving and securing the lower end of the piston rod 22. To thisend the piston rod'bore 20c contains an enlarged annular portion 20dintermediate its length. The lower end of the piston rod is providedwith an outwardly and downwardly tapered surface 22a terminating with afirst enlarged annular portion 22b. A split bushing 54 is complementaryto the lower end of the piston rod 20, having annular recesses 54c, 54dreceiving enlarged annular portions 22c and 22d of the piston rod 22.The split bushing 54 is received within the piston rod bore 200 belowthe annular portion 20d thereof.

Within the annular portion 20d is positioned a pair of wedge rings, afirst one 56, of which is of generally angular cross section having anupper surface 56a tapered upwardly and out wardly. The second wedge ring57 is provided with a lower surface 57a tapered upwardly and outwardlycomplementally engaging the tapered surface 56a of the lower wedge ring56, and additionally having an inner surface 571; tapered inwardly anddownwardly. The wedge rings 56 and 57 are split topermit their assemblywithin the annular portion 20d of the ram housing 20a. A rod retaininggland 60 extends into the upper cylindrical portion of the piston rodbore 200, secured to the housing 20a in any suitable manner as by thestuds 61, and is provided with a lower outer chamber 60a taperinginwardly and downwardly so as to engage complementally the surface 57bof the wedge ring 57, and additionally is provided with an inner taper60b loosely conforming to the tapered surface 22a of the piston rod 22,and tapering downwardly and outwardly as best illustrated in FIG. 6. Aplurality of dowel pins 62 align the two sections of the gland 60.

It will be understood that the split bushing 54 is loosely held withinthe piston rod bore 200, and aligned by the enlarged annular portions220 and 22d of the piston rod. The complementary tapered surfaces 560and 57a of the wedge of rings 56 and 57 provide for tightening of therings within the annular portion 20d of the housing 20a as the upperring 56 is wedged outwardly by the engagement of the chamfer 60a andtapered surface 57b. Thus the piston rod 22 is secured to the ramassembly 20 sufficiently loosely to permit minor misalignment andpercussion movement of the parts without binding or wedging.

The lower end of the piston rod 22 rests against a ram plate 64, FIG. 4,bearing against a ram cushion 65 of lead or other suitable material. Theram plate 64 and ram cushion 65 are between the piston rod 22 and theram point 24, transmitting the load of the piston 21 and the piston rod22 to the ram point 24.

The slide bar 40 is secured to the ram assembly 20 for vertical movementtherewith. More specifically, the ram housing 20a is provided with acounterbore through opening 68 having an enlarged upper portion 68a anda smaller or reduced diameter lower portion 68b, FIG. 5. The slide barterminates in a lower cylindrical portion 40a received within the upperportion 68a of the through opening 68, seating against a lower seatingring 69. The seating ring 69 has an upper spherical surface 690, and theslide bar 40 has a lower spherical surface 60b in engagement therewith.The slide bar 40 is retained within the through opening 68 by means of aflexible cable assembly 70 having an upper threaded fitting 71 threadedinto a complementary threaded opening in the lower end of the slide bar40, and having a a lower threaded fitting 72 connected therewith bymeans of a flexible rope 73. Suitable lock means, such as the nuts 74,fasten the slide bar 40 to the ram assembly 20.

The trip 35, in the illustrated embodiment, is provided with a recess35a FIGS. 7 and 8, containing a'detent ball 76 biased outwardly againsta surface 290 of the steam chest 29 by a compression spring 77. Thesurface 29a is provided with a pair of depressions 78 so that the ball76 will lock therein at the two positions of travel of the trip 35.

From the foregoing it will be understood that a percussion hammeraccording to the present invention is suitable for driving pile and likeapplications, and may readily be converted from one size to another bythe mere addition of removable weights 50 to the ram assembly 20.Moreover, the piston rod 22 and the slide bar 40 are secured to the ramassembly 20 in a new and novel manner which eliminates many of thedifficulties heretofore encountered. In addition, bouncing of the valveis eliminated by the addition of suitable detent means to lock the trip35 into a desired position.

Although the present invention has been described by reference to only asingle embodiment thereof, it will be apparent that numerousmodifications and other embodiments may be devised by those skilled inthe art.

I claim:

1. A percussion hammer of the type including:

a cylinder;

a piston operable in said cylinder;

a ram assembly provided with cavity means adapted to receive removableweights, said ram assembly having a centrally located piston rod borefor receiving one end of a piston rod;

removable weight means in said cavity means;

a piston rod connected to said piston and having one end extending intosaid bore, said one end having enlarged annular means;

a split bushing secured over said enlarged annular means;

a split piston-rod-retaining gland extending into said bore retainingsaid bushing;

means securing said retaining gland in said bore;

said bore being provided with a counterbore for securing a slide bar;

valve means for cycling working fluid into said cylinder, said valvemeans including a valve chamber and a multiposition valve elementmovable in said chamber;

a slide bar operatively positioned to control said valve means having alower and fitting into said counterbore and a flexible connecter, oneend of which isconnected to the lower end of said slide barand extendingthrough said counterbore, said flexible connecter being secured withinsaid counterbore; and

detent means retaining said valve element in one of its positions untilactuation thereof by said slide bar to the other of its positions.

2. A percussion hammer of the type including:

a cylinder;

a piston operable in said cylinder;

a ram assembly having a centrally located piston rod bore for receivingone end of apisto'n rod, said bore being provided with an annular,enlarged'portion intermediate its ends; a

a piston rod connected to said piston and having one end extending intosaid bore, said one end having a plurality of enlarged annular portions,and having an outwardly and downwardly tapered surface;

a split sleeve engaging a portion of said one end and fitted within saidbore;

a pair of split wedge rings adaptedto wedge within said annular enlargedportion;

a split piston-rod-retaining gland extending into said bore around saidrod and including a spaced complementary outwardly and downwardlyextending chamfer converging said outwardly and downwardly taperedsurface, said gland including a tapered surface engageable with one of Isaid retaining rings wedging said ring outwardly; means securing saidretaining gland in said bore;

actuating'means operatively connecting said valve means and said ram tocontrol the sequence of fluid flow into and out of said cylinderproviding for repetitively cycling said piston and ram.

3. A percussion hammer as set forth in claim 2 wherein the lower one ofsaid retaining rings is of generally angular cross section, having anupper surface inclined upwardly and outwardly the upper one of saidretaining rings having a lower surface complementary to saiduppersurface tapering upwardly and outwardly, said upper ring alsohaving an inner I valve means for cycling working fluid into saidcylinder; and

surface tapering inwardly and downwardly and in engagement with aninwardly and downwardly tapering outer surface of said gland wherebysaid gland wedges said upper ring outwardly to wedge said retainingrings within said enlarged annular portion.

4. A percussion hammer as set forth in claim 2 including: i

a ram point extending from the other end of said bore; and

a ram cushion between the lower end of said piston rod and said rampoint. a

5 A percussion hammer of the type including:

a cylinder;

a piston operable in said cylinder;

a ram assembly provided with a through counterbore for securing a slidebar;

a piston rod interconnecting said piston and said ram assembly;

a valve means for cycling working fluid into said cylinder;

a slide bar operatively positioned to actuate said valve means tocontrol the sequence of fluid flow into and out of said cylinder toprovide for said repetitive cycling of said piston and ram, said slidebar having a lower cylindrical portion fitting into said counterbore;

a flexible connecter having one end connected to the lower end of saidslide bar and extendingthrough said counterbore; and

means adjustably securing the other end of said flexible connecter insaid counterbore. 6. A percussion hammer as set forth in claim 5 whereinsaid flexible connecter includes a length of flexible rope havingthreaded fittings at each end, one of said fittings being threaded intothe lower end of said slide bar, the other of said fittings extendingthrough said counterbore and locked therethrough by the last mentionedmeans.

7. A percussion hammer of the type including:

a cylinder;

a piston operable in said cylinder;

a ram assembly; p

a piston rod interconnecting said piston and said ram;

valve means for cycling working fluid into said cylinder, said valvemeans including a valve chamber and a multipo sition valve elementmovable within said chamber;

cam means for moving said valve element to a first position when saidpiston is near the bottom of its stroke to supply pressurized fluid insaid cylinder to raise said piston and to a second position when saidpiston is near the top of its stroke to exhaust the working fluid frombelow said piston;

a slide bar operatively connected to said ram responsive to the positionof said piston for moving said valve element between said positions; and

detent means retaining said valve element and said cam means in adesired one of said positions until actuation thereof to the other ofits positions by said slide bar.

1. A percussion hammer of the type including: a cylinder; a pistonoperable in said cylinder; a ram assembly provided with cavity meansadapted to receive removable weights, said ram assembly having acentrally located piston rod bore for receiving one end of a piston rod;removable weight means in said cavity means; a piston rod connected tosaid piston and having one end extending into said bore, said one endhaving enlarged annular means; a split bushing secured over saidenlarged annular means; a split piston-rod-retaining gland extendinginto said bore retaining said bushing; means securing said retaininggland in said bore; said bore being provided with a counterbore forsecuring a slide bar; valve means for cycling working fluid into saidcylinder, said valve means including a valve chamber and a multipositionvalve element movable in said chamber; a slide bar operativelypositioned to control said valve means having a lower and fitting intosaid counterbore and a flexible connecter, one end of which is connectedto the lower end of said slide bar and extending through saidcounterbore, said flexible connecter being secured within saidcounterbore; and detent means retaining said valve element in one of itspositions until actuation thereof by said slide bar to the other of itspositions.
 2. A percussion hammer of the type including: a cylinder; apiston operable in said cylinder; a ram assembly having a centrallylocated piston rod bore for receiving one end of a piston rod, said borebeing provided with an annular, enlarged portion intermediate its ends;a piston rod connected to said piston and having one end extending intosaid bore, said one end having a plurality of enlarged annular portions,and having an outwardly and downwardly tapered surface; a split sleeveengaging a portion of said one end and fitted within said bore; a pairof split wedge rings adapted to wedge within said annular enlargedportion; a split piston-rod-retaining gland extending into said borearound said rod and including a spaced complementary outwardly anddownwardly extending chamfer converging said outwardly and downwardlytapered surface, said gland including a tapered surface engageable withone of said retaining rings wedging said ring outwardly; means securingsaid retaining gland in said bore; valve means for cycling working fluidinto said cylinder; and actuating means operatively connecting saidvalve means and said ram to control the sequence of fluid flow into andout of said cylinder providing for repetitively cycling said piston andram.
 3. A percussion hammer As set forth in claim 2 wherein the lowerone of said retaining rings is of generally angular cross section,having an upper surface inclined upwardly and outwardly the upper one ofsaid retaining rings having a lower surface complementary to said uppersurface tapering upwardly and outwardly, said upper ring also having aninner surface tapering inwardly and downwardly and in engagement with aninwardly and downwardly tapering outer surface of said gland wherebysaid gland wedges said upper ring outwardly to wedge said retainingrings within said enlarged annular portion.
 4. A percussion hammer asset forth in claim 2 including: a ram point extending from the other endof said bore; and a ram cushion between the lower end of said piston rodand said ram point.
 5. A percussion hammer of the type including: acylinder; a piston operable in said cylinder; a ram assembly providedwith a through counterbore for securing a slide bar; a piston rodinterconnecting said piston and said ram assembly; a valve means forcycling working fluid into said cylinder; a slide bar operativelypositioned to actuate said valve means to control the sequence of fluidflow into and out of said cylinder to provide for said repetitivecycling of said piston and ram, said slide bar having a lowercylindrical portion fitting into said counterbore; a flexible connecterhaving one end connected to the lower end of said slide bar andextending through said counterbore; and means adjustably securing theother end of said flexible connecter in said counterbore.
 6. Apercussion hammer as set forth in claim 5 wherein said flexibleconnecter includes a length of flexible rope having threaded fittings ateach end, one of said fittings being threaded into the lower end of saidslide bar, the other of said fittings extending through said counterboreand locked therethrough by the last mentioned means.
 7. A percussionhammer of the type including: a cylinder; a piston operable in saidcylinder; a ram assembly; a piston rod interconnecting said piston andsaid ram; valve means for cycling working fluid into said cylinder, saidvalve means including a valve chamber and a multiposition valve elementmovable within said chamber; cam means for moving said valve element toa first position when said piston is near the bottom of its stroke tosupply pressurized fluid in said cylinder to raise said piston and to asecond position when said piston is near the top of its stroke toexhaust the working fluid from below said piston; a slide baroperatively connected to said ram responsive to the position of saidpiston for moving said valve element between said positions; and detentmeans retaining said valve element and said cam means in a desired oneof said positions until actuation thereof to the other of its positionsby said slide bar.